A brief about single seed descent and multiline varieties. course- Genetics and Plant Breeding

1. VASANTRAO NAIK MARATHAWADA KRISHI VIDYAPEETH , PARBHANI
DEPARTMENT OF AGRICULTURAL BOTANY
ASSIGNMENT ON TOPIC – SINGLE SEED DESCENT METHOD
AND MULTILINE VARIETIES
SUBMITTED BY – SHEETAL TIRKEY
REGISTRATION NO. 2019A/35M
M.Sc ( GPB I year )

2.  Single seed descent method is a modification of bulk
method.
 First proposed by Goulden (1939) and later modified by Brim
(1966).
 Instead of bulking whole seed lot of selected plants, a single
seed is selected randomly from each selected plant to make
bulk.

3.  This method involves less record keeping works better where
the main focus is on improvement of quantitative traits or
characters such as yield and earliness, rather than qualitative
traits or characters such as flesh color and disease resistance.
 But, it does not involve selection process mainly artificial, so
chances of loosing superior plants are comparatively more and
because of the same reason does not eliminate weak plants
early such as in other methods.

4.  Single Seed Descent (SSD) Method includes stages as
described below
STEPS DETAILS
Hybridization Crossing of selected parents
F1 generation F1 seeds grown and bulk harvested.
F2 generation F2 seeds grown .One seed from each plant is selected randomly and mixed.
F3 generation F3 seeds are grown and harvested as above.
F4 and F5 generation The similar procedure as above is carried out.

5. STEPS DETAILS
F6 generation F6 seeds are planted. Selection for
superior plants is conducted and selected
ones are harvested separately. Number
of plants could range from150 to 500.
F7 generation The main point in this step is individual
plant progenies are grown and selected
plants are harvested in bulk
.F8 generation Preliminary yield trials and quality tests
are conducted.
F9 to F10 or F13 generation
Co-ordinated yield trials and tests for
resistance and quality are conducted.
F11 of F14 generation Seed multiplication for distribution

6. SCHEMATIC REPRESTATION OF SINGLE SEED DESCENT METHOD

7.  Requires little space.
 Saves time. Extensive field trials are not required.
 Little record keeping.
 Easy method to handle populations, handles large number of
crosses.
 Good for traits with low heritability.
 Natural selection has little influence.

8.  Little scope for natural selection
 Maximum productivity is established in F2 generations,
superior plants may be lost
 No recombination occurrence among selected lines
 Must evaluate large numbers of inbred lines to find out
superior ones.

9. Barley variety – glacier,arivat, beecher,gem
Indian mustard- narendra rai

10. Author(s): Kulbhushan Saxena; Rachit K Saxena; Rajeev KVarshney; M Prasad International Crops Research Institute for the Semi-Arid Tropics,
Patancheru, India
Abstract –
•Long duration required for generation advancement in pigeonpea [Cajanus cajan (L.) Millsp] is one of the major
bottlenecks in realizing rapid genetic gains.
•Therefore, a technology for rapid generation turnover is warranted to facilitate the development of new cultivars and
recombinant inbred lines.
•Breeding of early‐maturing cultivars has now opened up the possibility of rapid generation advance (RGA) in this crop.
•This paper reports the development of an RGA technology that integrates the germination of immature seeds with single
seed descent method of breeding.
•RESULT-The results showed that immature 35‐day‐old seeds can be used successfully to turn over a generation of
pigeonpea with 100% seed germination. These way 3/4 successive generations can be grown within a year.The
methodology presented in this study will accelerate the breeding process for breeding cultivars and develop rapidly the
materials required for genomics research in pigeonpea.

11. ABSTRACT-
•The comparative efficiency of three selection methods, viz., pedigree, modified bulk and (SSD) were assessed in F3, F4,
F5 and F6 generations of a cross combination Moroberekan/IR20 of rice.
• Bulk population showed superiority over pedigree for grain yield, panicle length, number of panicles, number of tillers
and harvest index in F3 generation. Pedigree method was found to be superior over bulk and SSD for grain yield per plant
in F4 and F5 generations. In the three breeding methods, mean values of grain yield showed directional shift across the
generations.
•In F6 generation, the pedigree-derived lines showed higher superiority over mean value than lines derived from SSD and
modified bulk for grain yield, number of panicles and harvest index. No significant differences existed between pedigree
and modified bulk-derived F6 lines for grain yield and harvest index.
•Inter-generation correlation coefficients were significant and positive between all the generations for grain yield, number
of tillers and number of panicles. Significant and positive correlations were observed between these three characters
across generations supporting the intergeneration correlation results .Visual selection based on the number of tillers and
number of panicles per plant was very effective for increasing yield in bulk and pedigree methods.

12. Author(s): R P Singh; B D Singh; R N Singh, Department of Genetics and Plant Breeding, Institute of Agricultural
Sciences, Banaras Hindu University.
Abstract :
•Two breeding methods, single-seed descent (SSD) and bulk (B) were compared in the
segregating generations of two crosses (HG19 x Black Neelalu (BN) and ML 5 x BN) of
mungbean,Vigna radiata (L.) Wilczek.Yield trials were grown in F3, F4 and F5 generations.
•There was no evidence for a directed shift in mean performance for days to maturity, No.
of branches and seeds/pod.
•There were sporadic differences in variance and CV estimates of bulk and SSD populations
most likely due to sampling error.
•The estimates of heritabllity and genetic advance were moderate to high, indicating that
improvement through selection would be feasible.
• RESULT-There was no consistent difference in the expected genetic advance from the
three SSD and the bulk populations.

13. Author(s): Jiban Mitra; R B Mehra, Division of Genetics, Indian Agricultural Research Institute, New Delhi
Abstract :
Three breeding methods, viz., pedigree, single seed descent and random bulk
were compared for their relative efficiency in terms of change in population mean
in F4 over F3 and in F5 over F3 as well as F4 generations for yield and its
components in two crosses of grasspea, namely, RED x P 28 and RED x EC
242692.
•RESULT- single seed descent method proved to be superior to random bulk and
pedigree methods in showing maximum changes in population mean for
different characters, whereas random bulk method showed the worst
performance in this regard.

14. Author(s): S Rajan; KV Peter, College of Horticulture, Kerala Agricultural University, Vellanikkara,Trichur, Kerala
Abstract :
Of the four methods of selection, viz, mass, pure line, ssdes and bulk, employed in
tomato improvement, the ssdes method was found superior in breeding for
number of fruits/plant, yield/plant, early flowering, fruit set and harvest, and fruit
weight.
• RESULTThe level of resistance to bacterial wilt increased from 77.87 to 90.14%
under ssdes method

15. Multiline variety is a mixture
of several pure lines of similar
phenotype(height, seed color
flowering time, maturity time
and various other agronomic
characteristics) but have
different genes for the
character under consideration
the disease resistance means
these are isogenic lines. At
the same time they do not
reduce the yielding ability of
each other when grown in
mixture (i.e. compatible).

16. The development of a multiline consists of four important steps:
(1) Selection of recurrent parent,
(2) Selection of donor parents,
(3)Transfer of resistant genes into recurrent parent, and
(4) Mixing of seed of the isogenic lines.

17. These are briefly discussed below:
(1) Selection of Recurrent Parent:
The recurrent parent should be a high yielding popular variety.The recurrent parent should be the best cultivar of a
region.
(2) Selection of Donor Parents:
Parents with resistance to various races of a disease should be chosen as donor parents.The resistance should be
thoroughly examined under artificial epiphytotic conditions before use of the donor parents in the crossing
programmes.The donor parents should be adapted varieties as far as possible.
Because in un-adapted parents disease resistance is sometimes linked with several un-desirable characters and
transfer of resistant genes from such parents to the recurrent parent becomes difficult task. Several donor parents
are selected to incorporate different resistant genes against various races.
(3)Transfer of Resistance:
The resistant genes are transferred from donor parents to the recurrent parent through a series of several separate
backcross programmes. Generally 4-5 backcrosses are sufficient to retain the genotype of recurrent parent with
added resistance in the backcross derivatives.The backcross derivatives are evaluated for disease resistance during
backcrossing and also at the end of backcrossing.The desirable lines from each backcross are mixed to form an
isoline.
(4) Mixing of Isolines:
The various isolines developed by various backcrosses are mixed together to constitute a multiline cultivar.
Generally 6-10 isolines are mixed to constitute a multiline cultivar.

18. Advantages of Multiline Variety
•At the time of disease outbreak, only one or few lines of the mixture get attacked, others
remain resistant. So the loss to the farmer is comparatively less.
•Multiline varieties are more adaptive to environmental changes than individual pure line.
Disadvantages of Multiline Variety
•Races of pathogen change as time goes on, so farmer has to change seeds every few years
which contains seeds of lines resistant to new pathogen races.
•No improvement in yield or other characters
•Takes more time to develop new variety, in the due course of time new pathogen races may
evolve.
•Costly
•All the lines constituting multiline variety may get attacked by the new race of pathogen.
•Not suitable for cross pollinated crops

19. Examples of Multiline Variety
•Kalyan sonaWheat variety Kalyan sona is the suitable example to explain the concept.
This variety was originally resistant to brown rust. Later on became susceptible to new
races of pathogen. Several pure lines with different resistance genes are produced
through backcross breeding using one recipient or recurrent parent.The donor parents
are the one with different genes for the disease resistance, every donor parent is used in
separate back cross program. Because of this each line receives different gene for
disease resistance according to the type of pathogen. Five to ten of such lines with
different alleles for disease resistance are mixed to develop multiline variety.The lines
to be mixed are determined by the races of the pathogen relevant to the area
considered.
•MLKS11 (8 closely related lines)
•KML7404 (9 closely related lines)

20. Author(s): H N Pandey; MV Rao
Affiliation: New Delhi,
Abstract :
A multiline development programme was started to introduce diversity of genes for stem rust resistance in two durum varieties,
namely NI 146 and HD 4519, through backcrosses using 14 diverse donors. Susceptible components 1a pure, stand showed high
rate of rust spread leading to high rust incidence. Multilines showed significantly low rate (67.4% to 84.0%) of rust spread over
the mean spreads of their individual components and maintained high degree of population resistance.The susceptibility level
of multilines did not increase proportionately with increase In the percentage of susceptible components in the multiline
population.
RESULT –The multiline populations showed up to 8.5% increase in yield over the mean yields of their components, considered
individually,and gave significantly higher yields (15.5% to 21.0%) over the most susceptible component under heavy disease
pressure. Even if 40% of the components of a multiline were susceptible to the most dominant and prevalent races of stem
rust, their composite population behaved like a resistant line having no adverse effect on yield.Compared to the recurrent
variety, multilines also showed better yield potential over locations.

21. Author(s): K S Gill;Virendra Kumar; G S Nanda
Affiliation: Department of Plant Breeding, Punjab Agricultural University, Ludhiana
Abstract :
Variation in the multilines of ‘PV 18’ variety and their components with respect of days to flowering, plant height, number of
tillers per meter, ear length, number of spikelets, grains per ear, seed size, grain yield and reaction to yellow and brown rusts has
been studied for two years.There was considerable variation for these traits among 212 components that were studied during
1973–74. Based on agronomic characters, yield and rust reaction, 84 of these were utilised to compose 12 multilines of different
height and maturity groups. On an average there were 8 components in each multiline. Some of the multilines outyielded the
recurrent parent ‘PV 18’ whereas in other cases the yield of the multilines was on a par with yield of ‘PV 18’. Multilines were
decidedly better in their rust resistance and only in case of PVML 5 (brown rust) and PVML 11 and 13 (yellow rust) the reaction
was more than 5S as against many of components where rust reaction was higher than this limit. PV 18 had an attack of 40S
and 60S of yellow and brown rust respectively.The prospects of multilines have been discussed in the light of the results
obtained.

22. K. S. GILL, G. S. NANDA, GURDEV SINGH and S. S. AUJLA
Department of Plant Breeding, Punjab Agricultural University, Ludhiana, India
ABSTRACT
The variation among the component lines of the KSML 3 (a multiline based on cultivar
Kalyansona, spring bread wheat) was studied for agronomic characteristics. For days to
earing and plant height the variation was small.This helped in imparting uniformity to the
multiline.The lines had an improved tillering ability and had larger seeds.This partially
explained the increased yield potential of the multiline as compared with Kalyansona. All
the lines were susceptible only to one or two races of the yellow and brown rust. In no case
any race was virulent against all the lines. In the field all the lines were resistant to both
rusts.

23.  Plant breeding – principles and method by B.D Singh
 http://theagricos.com/plant-breeding/single-seed-descent/
 http://theagricos.com/plant-breeding/multiline-variety/
 http://www.botanylibrary.com/plant-breeding-2/breeding-
methods/multiline-breeding/multiline-breeding-merits-
demerits-methods-crop-improvement-botany/14347
 JOURNALS from
https://www.icar.org.in/content/consortium-e-resources-
agriculture-cera